At Bravo's trial, prosecutors alleged that Bravo poisoned Aguilar with the sleeping aids mixed in a sports drink.

In this evidence photo, a sports drink bottle and sleeping aids are pictured among other items found in Bravo's car.

Prosecutors claim that after Bravo poisoned Aguilar, he then strangled him.

The prosecution presented this belt found in Bravo's SUV, pictured here in this evidence photo, as a theory for how Bravo killed Aguilar.

In this evidence photo, pieces of duct tape are pictured near where Aguilar's body was found in a forest in rural Levy County, Florida, about 60 miles southwest of Gainesville.

When Aguilar wouldn't answer his phone hours after he went to meet Bravo, Friman said she started to panic. Friman then said she made Bravo go with her to the police to report him missing.

Bravo was charged with first-degree murder on Sept. 28, 2012.

In police interrogation tapes played in court, Bravo told police that he met up with Aguilar on the night of his death and that the two got into an argument.

"He got out of the car and I fought him and after that, I remember going in the car and I remember seeing him in my rear view mirror while I was driving away," Bravo told police during the interrogation.

Aguilar's backpack, seen here in this evidence photo, was key evidence at Bravo's trial. The backpack was found in Bravo's apartment hidden inside of another backpack.

Aguilar's body was found 22 days after his disappearance.

On Oct. 19, 2012, Bravo pleaded not guilty to murder and kidnapping charges. He pleaded not guilty in November to five additional charges in Aguilar's death.

On Aug. 16, 2014, a jury deliberated for almost four hours before finding Bravo guilty of first-degree murder and six other counts in Aguilar's death.

Bravo was sentenced to life in prison without the possibility of parole.

Upon hearing the guilty verdict, Friman said she was relieved.

"I was happy I didn't have to worry anymore," Friman said.

Watch the full story on ABC News' "20/20" TONIGHT at 10 p.m. ET.

After Christian's death, the family launched the Christian Aguilar Search and Rescue Foundation to create a network of trained dogs ready to be dispatched to help search for missing people all across the country. For more information, visit their website, http://casark9.com/